Cylinder grinder



Aug. 30, 1938.

J. M. KROHN r-rr AL 2,128,751

CYLINDER GRINDER Filed Nov. 22, 1954 5 Sheets-Sheet l A7 F 5 l [ill 5' A 25 5;: TI" 4? L 32 S I INVENTOR. I v John M Mv/m &

ATTORNEY.

Aug. so, 1938. 'JZM KRbH N ETAL 2,128,751

CYLINDER GRINDER File N v. 22, 9 4 5 Sheets-Sheet 2 36 34 I f/YTGRS'.

37 BY John M Amfifl 3 Eugene #500,050

Aug. 30, 1938. JJM. KROHNQ'EI' AL 2 CYLINDER GRINDER Filed Nov. 22, 1934 5 Sheets-Sheet s portable grinding machine which is light and v Fatented Aug. 30, 1938 John M. Krohu,

inc, Eugene H. Son.v West Allis,

Application Novemmr 22, 1934, Serial No. 1543M This invention relates to cylinder grinding or honing machines particularly adapted to grind or finish engine cylinders.

In the grinder, art considerable difiiculty has I been encountered in grinders in which a plurality of stones are mounted on a single block because the stones drift and cause the resulting hole to vary from the true perpendicular by considerable amounts. This is particularly true in portable machines in which the construction is relatively light and the mounting insecure.

One object of the invention therefore is to provide a cylinder grinding machine of the type which will grind the cylinder with the axis thereof truly perpendicular to the axis of the crank shaft.

Another object of the invention is to provide a eiilcient and which will rebore a hole truly perpendicular to the crank shaft under allv conditions. A further object of the invention is to provide a grinding element with an increased range of expansion having an improved mechanism to effect positive and uniform radial expansion of the grinding diameter.

In most of the grinders now on the market the "stones are mounted on conical'expanders which provide for a limited expansion only. These expanders have the obvious disadvantage of allowing one end of the stone to grind at a greater radius than the other end, causing variation in the diameter of the hole.

It-is another object oi the present invention to provide a grinder mounting which will maintain the stones at a given diameter throughout the length thereof and which will increase the range of diameters through which the grinder will operate. v

. Another object 01' the invention is to provide an improved mechanism for automatically-expanding the diameter of the stones at the beginning oi the longitudinal strokes of the stones.

Other objects of the invention are to increase the flexibility and range of adaptability o! cylinder grinding and honing machines, toproduce a machine which will be relatively simple to manu- -facture and use. and which will reduce the initial cost of grinding and the cost of reboring.

Other objects will be apparent from the following description.

Two embodiments oi the invention are disclosed in the accompanying drawings and will be described in theiollowingspeciflcation.

In the drawings:

Fig. 1 is an elevational view partly in crosssection of a cylinder grinding or honing machine as applied in the manuiacture of engines, with a cylinder blockin place. r

Fig. 2 is a side view of the machine shown in Fig. 1 with the cylinder block removed.

Fig. 3 shows a cross-section of the lower portion 0! the automatic stone expanding mechanism of the machine as shown in Figs. 1 and 2.

Fig. 4 is a cross-section of the upper portion of the automatic stone expanding mechanism shown in Figs. 1 and2, and is a continuation of Fig. 3.

Figs. 5 and 6. are cross-sections on the lines 5-5 and of Fig. 3 lookingin the direction of the arrows.

Figs. '1 and 8 are crcss sections on the lines 1-1 and 8-8 respectively of Fig. 6 loomng in the direction of the arrows.

Fig. 9 is a cross-section on the line 9-4 of Fig. 4 looking in the direction of the arrows.

wand 11 are cross-sections on the lines i0--lll and il--ll respective y. of Fig. 3, looking in the direction of the arrows.

Fig. 12 is a vertical cross-section of a manual expander used on portable grinding machines.

Fig. 13 is a cross-section on the line l3-l3 of Fig. 12 looking in the direction oi the arrows.

Fig. 14 is a vertical cross-section through the lower support in a portable grinding or honing machine of the type shown in Fig. 12.

Fig. 15 is a cross-section on the line iB-IB of Fig. 14 looking in the direction of the arrows.

In the drawings in which like numerals indicate like parts throughout the several views two embodiments of the invention are disclosed. Figs. 1 to 11 inclusiveshow a factory or production type cylinder grinder .tor use in the manufacture of engines or the like, in which a relatively heavy fully automatic machine is required, while Figs.-12 to 15 inclusive show a portable type machine designed primarily for reboring or honing work in garages. J

Referring-to Figs. 1 and 2 which show complete assemblies of a production type machine in two planes, the grinder is shown mounted on a standard 2|, which extends over agrinding table it. The table 2| holds a cylinder block 32 com-. prising one or more cylinders to be ground and honed to also by a grinder or hone 28.

The standard has a bracket 24 formed on one side thereof which supports a motor 26 or other prime mover. The motor 25 operates a pair of bevel gears 26-40 through a pulley and gears 26 and 30 lnter-.

posed between the gears 26 and the gear 28 to provide a plurality of desirable speeds. The changes in gear ratio are effected through a pair of shift levers 3| and 32 in the usual manner.

The driving gear 28 turns a gear 33 which is splined on a hollow spline shaft 34 which rotates the hone 23. The spline shaft 36 runs in bearings 35 and 36, with interiorly splined sleeves 31 and 38 interposed therebetween. This permits free rotation of the spline shaft 36 as well as free axial movement.

The spline shaft 34. is connected 'with the grinder or hone 23, by a flanged coupling 39 so that, rotation of the spline shaft rotates the stones and reciprocation of the spline shaft causes a corresponding reciprocation of the stones.

The hone 23 is reciprocated by means of a hydraulic motor comprising a double acting cylinder 46 containing a piston 4| which drives a piston.

rod 42. Fluid, such as oil, is supplied from a pump 43 through feed pipes 44 and 45 to the upper and lower ends respectively of the cylinder 46 to reciprocate the piston 4|. A valve 46 directs fluid from the pump 43 alternately tothe upper and lower sides of the piston 4|. While fluid is being delivered to one side of the piston 4| it is being withdrawn from the other side of the piston f through the valve 46 and returned to the pump 43. The valve 46 is operated by a finger 41 which actuates a double arm valve trip 48 at the opposite ends of the piston stroke to reverse the flow of fluid in the pipes 44 and 45.

As shown in Figs. 1, 3 and 4 the piston rod 42 terminates in a cup like plug 49 fitting in the interior of the hollow spline shaft 34. The plug 49 has a thrust bearing 56 which permits the transmission of longitudinal stress to the hone 23' while permitting free rotation of the hone relative to the piston rod 42.

The plug 49 is connected to a driving sleeve 5| which is suitably keyed to the interior of the spline shaft 34 so as to permit limited axial movement of the sleeve, relative to the spline shaft. Axial movement is transmitted from the sleeve 5| to the spline shaft 34 through a shoulder 52 formed on the interior of. the spline shaft on the lower end, andthrough a split ring stop 53, or its eguizalent, adjacent the upper end of the spline s a Provision is made for a small amount of lost motion between the driving sleeve 5| and the spline shaft 34. This lost motion occurs at the beginning of both the up and down strokes of the piston, and is utilized to expand the stones of the grinder or hone 23, in a manner described below.

Referring particularly to Figs. 5 to 8 inclusive, the grinder or hone 23 is composed of a plurality of stones 54 which are mounted on holders 55 supported by rods 56 which have gear teeth 51 cut in one side thereof. Each stone is supported-by two or more such rods to assure a rigid mounting in a mounting block 56, which contains gears 59 and 66 at the top and bottom respectively of the grinder which mesh with the teeth 51 in the rods 56 to alter or maintain the grinding radius. The gears 59 and 66 are of equal diameter and both keyed on shafts 6| which insures a uniform radial movement of both ends of the stones.

The gears 59 are provided with two sets of teeth, one of which meshes with the teeth 51 in the rods 56, and a second set, in a single plane, which engage with the teeth of a master gear 62 positioned on the upper part of the block '58 and located con- .centrically with the stones 54. gears 59 and 66 have blank portions to permit the Certain of the .initial diameter, from which point they are automatically expanded by the action of the driving sleeve 5| in the following manner.

The actuating shaft 63, Figs. 3 and 4, has a pair of cam slots 66 which are engaged by cam pins 61 fixed in actuating cones 68 and 69 which are mounted for limited axial movement on the shaft 63 and rotate therewith. The actuating cones carry overriding clutches 16 which are engaged by driving cones H and 12, which impart an axial movement to the actuating cones while the clutches prevent relative rotation between the driving and the actuating cones during driving.

One type of overriding clutch is shown in which the balls ride in a race having a ratchet section 16a cut in the inner face of the race so that the may also prove satisfactory.

The axial movement of the actuating cones 68 and 69 causes the pins 61 to move in the cam slots 66 and turn the actuating shaft, which expands the stones. By using two cam slots 66, as shown in Figs. 3 and 4, expansion can be made to occur I at the beginning of both' the up and the down strokes of the stones. The driving cones are keyed to rotate with the spline shaft 34, and are moved longitudinally in one direction by the driving sleeve 5| and returned by springs 13 which act againstoollars 14 fixed to the shaft 63.

The actuating cones 68 and 69 are constantly urged toward the driving cones 1| and 12 respectively, by springs 15 and 16. The springs 15 and 16 supply the necessary pressure between the driving and the actuating cones to cause the friction clutch 16 to drive. 4

Keys 11 and 18 are provided in the driving cones 1|- and 12 to permit limited lateral movement of the driving cones relative to the spline shaft 34 while preventing relative rotation between the two.

The actuating, cones 68 and 69 are positively disengaged from the driving cones 1| and 12 respectively, by wedge keys 19 interposed between the actuating cones 68 and 69 and the actuating shaft 63. The wedge key has a pair'of spaced fingers 86 and'8|. The flnger 86 has a spring 82 interposed between it and the small end of the actuating cone and a second, stronger spring 83 between it and an interior annular flange 84 on the driving cone.

When the driving cone 1| or 12 moves into contact with the actuating cone. 68 or 69 the annular flange 64 presses the wedge into engagement between the shaft 63 and the actuating cone so as to permit longitudinal movement of the cone in one direction only. When the driving cone 1| or 12 retracts, the actuating cone 66 or 69 is held against following until the annular flange 84 strikes the finger 8|. Contact of the flange 64 with the finger 8| breaks the connection between the cone 66 or 69 and the shaft 63.and enables the cone 66 or 69 to move back to its original position under the influence of the springs 15 and lower end of s earer I8. The spring 82 holds the wedge out of engagement with the keyway and permits the actuating cones 88 and 88 to'return to normal position as soon as the wedge is released. 8

Referring to Fig. 1, it will be seen that the the grinder or with a guide cylinder 85' which fits over a piston or guide rod 88. The rod 88 passes through the grinding table 2i and into a cylinder 8]. where a piston is attached to it for operation in the The upper and lower parts of the cyl-'- to the pump t8 and the pump is made operable after a predetermined number of strokes to withdraw the piston or guide .rod from the guide cylinder 88.

The guide cylinder and rod form a sup ort 1 for the lower end of the grinder and insure a equipment of this character,

truly perpendicular hole inder block.

Since garages and repair shops cannot put in a light hone has been developed using the principles disclosed above. except that it does not automatically expand the stones. This grinder is shown in Figs. 12 to 15 inclusive.

Fig. 14 shows the lower portionsof the grinding or honing machine for use in garages. The grinding or honing machine has a set of stones 88 mounted on a block 88. The block 88 is formed with'stub shafts 88 and 8| on the top and bottom thereof respectively.

The lower stub shaft 8i operates in a cylinder 82, which is fastened to the crank shaft 88 of the engine. The cylinder 82 forms a guide for the lower end of the grinder, and prevents drift of the stones. r

A yieldable support. generally designated 84 aids in maintaining 8i truly axial in the hole. The details of the support 84 are shown-in Figs. 14 and 15. The support 88 has a cylinder 88 which has a working fit on the exterior of the guide cylinder 82. The

cylinder 85 is constantly urged upward by a spring 88, and limited in its upward movement by a retaining sleeve 81, adjustably fixed to the lower end of the guide cylinder 82.

Yieldable fingers 88 are mounted for limitfd 5.

and are pressed outwardly by springs 88 into engagement with the walls of the engine cylinder.- A guide block I88 supports guide pins I8I which.

limit the radial movement of the lingers 88 and form guides'for springs 88.

The lower support or guide 841s fixed on the crank shaft 88 by means ofa saddle I82 which is clamped on the crank shaft and attached to the lower end of the guide cylinder 82.

In operation the grinder 88 reciprocateswith a length of the stroke slightly greater than'\ the cylinder. When the grinder block 88 comes in contact with the yieldable support 88 it shoves the cylinder 88 down against the action. of' the spring86, and forces the'guide block I88 and the lingers as out of the cylinder and permits the grinder 88 to hone the lower edge of the cylinder. upward in the cyl- When the grinder .88 goes inder, the lingers 88 again enter the. cylinder and form an additional support for the stubshaft 8|.

Referring to Fig. 12, the upper end of the grinder 88 ground by a frame (not shown) which clamps onthe upper surface of the cylinder block. I

Power is transmitted from an electric motor or other suitable power sourceito a shaft I88 which is'fastened to the stub shaft 88 by a siut hone, 28 .is provided to expand the stones as being ground in the cylthe guide rod or stub shaft.

fluid is delivered to is supported overthe cylinder to be collar 888 which turns freely on the stub shaft ,88

bevel gear 988 which is the stub shaft 88. The a housing I88; where it meshes with a bevel gear I81 on the side of the housing I88. The bevel gear I87 drives a bevel gear I88, as shown in Fig. 13, which is keyed on a shaft containing a worm I88.

The worm I88 turns a worm. wheel H8 which is mounted on the stub shaft 88. The worm wheel lid is made integral with a master gear iii", comparable to the master gear 88 described above. The master gear Iii operates gears 88 described above. and as shown on Figs. 5 to 8 inclusive.

Operation The hone shownin Figs. 1 to 11 inclusive is permanently mounted on the frame 28 and in and is attached to a' mounted to turn ou gear I88 is enclosed in order to grind or hone a cylinder, the cylinder 22 is placed on the table and the piston rod 88 brought up by suitable attached thereto. The with the stones retracted until the piston rod 86 engages with the cylinder 85.

Thehone is then moved to either the upper or lower end oi the stroke, at which point both operation of the piston hone 28 is then lowered the ciutchesfit are disengaged. [A key is inserted (Fig. 11) on a square end of the shaft carrying the worm 65 to expand the stones to the initial grinding diameter.

A counter (not shown) is set to completely withdraw the stones from the cylinder at the end of the predetermined number of strokes necessary to reach the required diameter. I

The stones are then started rotating through the gears 28, 28, 88, 28 and 88. At the same time the cylinder 88 to reciprocate. the stones in the cylinger 22.

At the beginning 0 t e down stroke of the hone t8 the sleeve tl mo es the driving cone I2 into engagement cone 88 and at the same time. the annular c'ollar 84 engages the spring 88 and forces the wedge key 88 into engagement between the cone 88 and the actuating shaft 88. Further movement of the driving cone I2 causes'the actuating cone to move down with the cam pin 81 engaging the cam slot 88 to turn stones a set amount.

when the hone 28 starts up, 12 is moved up by the spring I8 and disengages from the clutch '18 in the actuating cone. The actuating cone I8 is prevented from following by the wedgekey 88, which holds the cone 88 in its lowermost position until the key 88 is disengaged by upward pressure of the ring 88 on the finger 8 I Whenthe ring 88 engages the finger M to disengage the key 88 the spring ,82 acts to maintain the key. 88 disengaged while the spring I8 moves the cone 88 back to its original position.

It'will be noted that the cone is free to rotate on the shaft when disengaged from the driving cone l2, and hence they cam'pin 81 returns to its original position without turning the shaft 88. On the upstroke. a similar action takes place between the driving cone II and the actuating cone 88. When a predetermined number of strokes are completed, a counter (not shown) operates to withdraw the hone 28 from the cylinder 22 and at the same time the piston rod 88 is withdrawn with the clutch 10 m the actuating the shaft 88 and expand the the driving cone through the movable portion of the table ii to permit removal of the cylinder block.

- ter described comprising,

In operation, the portable hone shown in Figs. 12 to 15 inclusive is set on top of a cylinder block with a supporting frame (not shown) fixed to thetop of the block over a cylinder to guide the grinder or hone 23 axially into the cylinder.

The saddle'i02 is fixed to the crank shaft 93 with the latter at dead center. The fingers 98 are adjusted in the lower end of the cylinder 22 and the stub shaft 9! guided into the cylinder 92.

The grinder 23 may then be rotated by a motor (not shown) and at the same time the hone is reciprocated manually.

Expansion of the stones B8 is effected by stopping the motor and turning the graduated collar as explained above.

When the grinder 23 reaches the lower part of" the cylinder 22, the block Hill is pushed down by the lower edge of the grinder, which moves the fingers out of the cylinder and permits the lower part of the cylinder to be ground to the same diameter as the remainder of the cylinder.

When the grinder 23 movm up in the cylinder the spring 96 forces the fingers 98 up and into the cylinder to form an intermediate support between the upper and lower supports.

If desired the grinder shown in Figs. 12 to is inclusive may be reciprocated by a hydraulic drive similar to that shown in Figs. 1 and 2.

Having thus described the invention, it is realized that it is susceptible to various changes and modifications without resorting to invention. It is not, therefore, desired to limit the invention to the particular forms herein shown and described, but only by the scope of the appended claims.

What is claimed as new and desired to secure by Letters Patent is:

1. A cylinder grinding machine of the characa grinder mounting block adapted for axial reciprocation in a cylinder to be ground, and rotatable on the axis of the cylinder, a plurality of stones mounted axially on said block andadapted to expand radially thereto, means in said block to expand said stones radially, a hollow spline shaft having a driving connection with the block to rotate the same, means to reciprocate said block, an actuating shaft mounted in the spline shaft and having an operating connection with the stone expanding means to effect operation thereof, and means in said spline shaft, engageabie with said second named shaft to effect rotation of the second named shaft relati e to the spline shaft at a predetermined point in the axial movement of the grinder.

2. A cylinder grinding machine as defined in claim 1 including manual means to effect rotation of the actuating shaft relative to the spline shaft at predetermined points inthe stroke.

3. A cylinder grinding machine as defined in claim 1 in which the last named means includes a cam groove in the actuating shaft and a cam follower driven by the means to reciprocate the block.

4. A cylinder grinding machine as defined in.

.clamped on the crank shaft and yieldably en-.

gaging the sides of said-cylinder to engage the said supporting shaft and guide the lower end of the grinder to prevent drift.

"4. A cylinder grinding machine of the character described comprising, a plurality oistones mounted to reciprocate axially in a cylinder to be ground and expand radially therein, means to support the stones over an engine with the stones alined with the cylinder to be ground, means including a clamp attached to the crank shaft of the engine when the said shaftis at dead center and a guide cylinder and guide rod operable therein to maintain the lower end of the stones in alinement in the cylinder.

8. A cylinder grinding machine of the character described comprising, a plurality of stones mounted to move axially within a cylinder to be ground and expand radially therein. means to rotate and reciprocate said stones within the cylinder to grind the same, means on one end of said cylinder to maintain said stones alined in said cylinder, means on the other end of said cylinder to maintain said stones in alinement, and means in one end of said cylinder to form a brace between said stones and said last named support while grinding.

9. A cylinder grinding machine of the character described comprising, a plurality of stones mounted to move axially within a cylinder and expand radially therein, means on one end of said cylinder to maintain said stones alined in said cylinder, means on. the other end of said cylinder to maintain said stones in alinement, and means in one end of said cylinder retractable therefrom by the action of thestones to form a brace between said stones and said last named support.

10. In a cylinder grinder of the character described, a mounting block adapted to rotate about a vertical axis, a first pair of parallel racks mounted in apertures in said block intersecting the axis thereof, a grinding stone carried by said racks parallel to said axis, a second pair of parallel racks mounted in apertures in said block intersecting said axis at different elevations from said first pair of racks, a grinding stone carried by said second pair of racks parallel to said axis, a first pair of gears mounted to rotate together on a common axis and engaging the teeth of the first pair of racks to move the stone radially while maintaining the stone parallel to said axis, a. second pair of gears mounted to rotate together ona common axis and engaging the teeth of said second pair of racks to move the stone carried thereby radially while maintaining the stone parallel to'said axis, a master gear engaging one gear of each pair of gears to move both stones simul-: taneously, and means to rotate said master gear to effect expansion of the stones.

11. In a machine tool having radially expansible cutting elements, a hollow shaft mounted for rotational and limited axial movement and connected to the said cutting elements to effect area":

18. The spring 82 holds the wedge out of engagement with the keyway and permits the actuating cones 88 and 88 to return to normal position as soon as the wedge is released.

Referring to Fig. 1, it will be seen that the lower end of the grinder or hone 23.ls with a guide cylinder 85 which fits over apiston or guide rod 88. The rod 88 passes through the grinding table 2i and into a cylinder 81, where a piston is attached to it for operation in the The upper and lower parts ,of the cyl inder 81 are connected, to the pump 88 and the for the lower end of the grinder equipment of this character,

.or ,honing machine for stroke slightly greater than\ pump is made operable after a predetermined number of strokes to withdraw the piston or guide rod from the guidecylinder 88.

The guide cylinder and rod form a support and insure a truly perpendicular hole being ground in the cylinder block.

Since garages and repair shops cannot put'in a light hone has been developed using the principles disclosed above. except that lt does not automatically expand the stones. This grinder is shown in Figs. 12 to 15 inclusive.

Fig. 14 shows the lower portionrof the grinding use in garages. The grinding or honing machine has a set of stones 88 mounted on a block 88. The block 88 is formed with stub shafts 88 and 8| on the top and bottom thereof respectively.

The lower stub shaft 92, which is fastened to the engine. The cylinder 82 forms a guide for the lower end of the grinder, and prevents drift of the stones.

A yieldablev support. aids in maintaining the guide rod or stub shaft 8| truly axial in the hole. The details of the support 88 are shown in Figs. 14 and 15. The support 84 has a cylinder 88 which has a working fit on the exterior of the guide cylinder 82. The

M operates in a cylinder cylinder 88 is constantly urged upward by a I spring 88,*an'd limited in its upward movement by a retaining sleeve 81, adjustably fixed to the lower end of the guide cylinder 82.

Yieldableflngers 8i! are mounted for limited radial movement on the top of the cylinder 28,

- and are pressed outwardly by springs 88 into engagement with the walls of the engine cylinder.-

A guide block I88 supports guide pins l8i which.

limit the radial movement of the fingers 88 and form guides for springs 88.

The lower support or guide 88-is fixed on the crank shaft 83 by means of a saddle I82 which is clamped on the crank shaft and attached to the lower end of the guide cylinder 82.

In operation the grinder 88 reciprocates with a the length of the block 88 comes in cylinder. When the grinder contact with the yieldable support 84 it shoves the cylinder 88 down against the action of the spring 88, and forces the guide block I88 and the fingers 88 out of the cylinder and permits the grinder 88 to hone the lower edge of the cylinder."

When the grinder 88 goes-upward'in the cylinder, the fingers 98 again enter the cylinder and form an additional support for the stub shaft 8|. Referring to Fig. 12, the upper end of the grinder 88 is supported over the cylinder to be ground by a frame (not shown) which clamps on the upper surface of the cylinder block. 7

'Power is transmitted from an electric motor or other suitable power sourceto a shaft I88 which is fastened to the stub shaft 88 by a suitprovided vthe crank shaft 88 of generally designated 88 I collar I88 which turns freely on the stub shaft 88 v and is attached to a bevel gear 8 which is mounted to turnon the stub shaft 88. The gear 188 is enclosed in a housing I88, where it meshes with a bevel gear i8! on the side of the housing I88. The bevel gear l8! drives a bevel gear I88, as shown in Fig. 13, which is keyed on a shaft containing a worm i88.

The worm I88 turnsa worm wheel M8 which is mounted on the stub shaft 88. The worm wheel 8 is made integral with a master .gear iii, comparable to the master gear 88 described above. The master gear iii operates gears 88 to expand the stones as described and as shown on Figs. 5 to 8 inclusive.

i Operation The hone shownin Figs. 1 to 11 inclusiveis permanently mounted on the frame 28 and in ,order to grind or hone a cylinder, the cylinder 22 is placed on the table and the piston rod 88 brought up by suitable operation of the piston The hone 28 is then lowered rod the clutchesjit are disengaged. IA key is inserted (Fig. 11) on a square carrying the'worm 85 to expand the stones to the initial grinding dieter.

A counter (not shown) is set to of the predetermined number of strokes necessaryto reach the required diameter.

The stones are then started rotating through the gears 28, 28. 88, 28 and 83. At the same time hand is delivered to the cylinder 88 to reciprocate,

the stones in the cylin er 2?.

At the beginning oglt e down stroke of the hone 28 the sleeve 8i mo es the driving cone (2 into engagement with the cone 88 and at the same lar 88 engages the spring key 88 into ensazement between the cone 88 and. the actuating shaft 88. Further movement of the driving cone I2 causes the actuating cone "to move down with the cam pin 81 engaging the cam slot 88 to turn stones a set amount.

when the hone 28 starts up, 12 is moved up by the spring 18 and disengages from the clutch 18 in the actuating cone. The actuating cone I8 is preventedfrom following by the wedge key 88, which holds the cone 88 in its lowermost position until the key 88 is disengaged by upward pressure of the ring 84 on the finger 8i.

When the ring 88 engages the finger 8! to disengage the key 88 the spring 82 acts to maintain the key 88 disengaged while the spring 18 moves the cone 88 back to its original position.

Itwill be notedthat the cone-88 is free to rotate time. the annular colon the shaft when disengaged from the driving at the same time the piston rod 88 is withdrawn completely withdraw the stones from the cylinder at the end clutch ill in the actuating 88 and forces the wedse' end of the shaft the. shaft 88 and expand the the driving cone I ter described through the movable portion of the table 2| to permit removal of the cylinder block.

In operation, the portable hone shown in Figs.

12 to 15 inclusive is set on top of a cylinder block with a supporting frame (not shown) fixed to the top of the block over a cylinder to guide the grinder or hone 23 axially into the cylinder.

The saddle ".12 is fixed to the crank shaft 93 with the latter at dead center. The fingers 98 fingers out of the cylinder and permits the lower part of the cylinder to be ground to the same diameter as the remainder of the cylinder.

When the grinder 23 moves up in the cylinder the spring 96 forces the fingers 98 up and into the cylinder to form an intermediate support between the upper and lower supports.

If desired the grinder shown in Figs. 12 to 15 inclusive may be reciprocated by a hydraulic drive similar to that shown in Figs. 1 and 2.

Having thus described the invention, it is realized that it is susceptible to various changes and modifications without resorting to invention. It is not, therefore, desired to limit the invention to the particular forms herein shown and described, but only by the scope of the appended claims.

What is claimed as new and desired to secure by Letters Patent is:

1. A cylinder grinding machine of the characcomprising, a grinder mounting block adapted for axial reciprocation in a cylinder to be ground, and rotatable on the axis of the cylinder, a plurality of stones mounted axially on said block and'adapted to expand radially thereto, means in said block to expand said stones, radially, a hollow spline shaft having a driving connection with the block to rotate the same, means to reciprocate said block, an actuating shaft mounted in the spline shaft and having an operating connection with the stone expanding means to effect operation thereof, and means in said spline shaft, engageable with said second named shaft to effect rotation of the second named shaft relati e to the spline shaft at a predetermined point in the axial movement of the grinder.

2. A cylinder grinding machine as defined in claim 1 including manual means to effect rotation of the actuating shaft relative to the spline shaftat predetermined points in the stroke.

3. A cylinder grinding machine as defined in claim 1 in which the last named means includes a cam groove in the actuating shaft and a cam follower driven by the means to reciprocate the block.

4. A cylinder grinding machine as defined in claim 1 in which said last named means includes a releasable clutch.

5. A cylinder grinding machine adapted 1 grind the cylinders of an engine having a crank shaft, and comprising a grinder body having a supporting shaft on the lower side thereof, a plurality of stones mounted on said body to move axially therewith in the engine cylinder and expand radially thereto,means to reciprocate and rotate said stones within the cylinder, and means clamped on the crank shaft and engaging the supporting shaft to insure against drift in grindity of stones mounted on said body to move arially therewith in the engine cylinder and expand radially thereto, means to reciprocate and r0- tate said stones within the cylinder, and means clamped on the crank shaft and yieldably engaging the sides of said cylinder to engage the said supporting shaft and guide the lower end of the grinder to preventdrift.

7. A cylinder grinding machine of the character described comprising, a plurality of stones mounted to reciprocate axially in a cylinder to be ground and expand radially therein, means to support the stones over an engine with'the stones alined with the cylinder to be ground, means including a clamp attached to the crank shaft of the engine when the said shaft is at dead center and a guide cylinder and guide rod operable therein to maintain the lower end of the stones inalinement in the cylinder.

8. A cylinder grinding machine of the character described comprising, a plurality of stones mounted to move axially within a cylinder to be ground and expand radially therein, means to rotate and reciprocate said stones withinthe cylinder to grind the same, means on one end of said cylinder to maintain-said stones alined in said cylinder, means on the other end of said cylinder to maintain said stones in alinement, and means,

in one end of said cylinder to form a brace between said stones and said last named support while grinding.

9. A cylinder grinding machine of the character described comprising,

mounted in apertures in said block intersecting the axis thereof, a grinding stone carried by said racks parallel to said axis, a second pair of parallel racks mounted in apertures in said block intersecting said axis at different elevations from said first pair of racks, a grinding stone carried by' said second pair of racks parallel to said axis, a first pair of gears mounted to rotate together on a common axis and engaging the teeth of the a plurality of stones mounted to move axially within a cylinder and first pair of racks to move the stone radially while maintaining the stone parallel to said axis, a second pair of gears mounted to rotate together on a common axis and engaging the teeth of said second pair of racks to move the stone carried thereby radially while maintaining the'stone parallel to said axis, a master gear engaging one gear of each pair of gears to move both stones simultaneously, and means to rotate said master gear to effect expansion of the stones.

11. In a machine tool having radially expansible cutting elements, a hollow shaft mounted for rotational and limited axial movement and connected to the said cutting elements to efiect stroke, means including a support above the rotation thereof, means to expand said cutting elements radially, and means within said hollow shaft operable upon axial movement of said hollow shaft at a predetermined point in its stroke to operate the cutter expansion means.

12. In a cylinder grinder adapted to grind the cylinder of an engine having a crank shaft, a grinder element adapted to reciprocate in the cylinder, a support for the upper end of said grinder element above said cylinder, and a clamp fixed to the crank shaft of the engine at dead center, interengaging slidable members connected to the lower end of said grinder element and 14. A cylinder grinder as defined in claim. 12,

in which the interengaging slidable members include a guide cylinder attached to the clamp and a guide rod having a working fit in said cylinder and attached to said grinder.

,15. In a cylinder grinder adapted to grind the inner surface of an engine cylinder, a support for said grinder at one end of said cylinder, a

guide rod on the end of the grinder opposite said support, a support below said cylinder engaging said rod and permitting reciprocation and rotation thereof, and fingers on said support engaging the inner surface of said cylinder to center the support therein.

16. A grinder as defined in claim 15, including a plurality-of springs constantly urging said fingers into engagement with the cylinder, and means limiting the outward movement of the fingers. i

17. A cylinder grinder as defined in claim 15,

in which said last named support is retractable from the cylinder by action of the grinder.

18. Ina cylinder grinder of the character described, a grinder body adapted to rotate and reciprocate within a cylinder to be ground, a plurality of stones extending axially on said body and adapted to expand radially thereto, means to expand the stones at the beginning of the stonesto efiect rotation and reciprocation thereof, a support below said stones including a guide cylinder with a, guide rod reciprocable therein to prevent drifting of the grinder, and means independent of said upper support to withdraw the lower support at the conclusion of the grind: ing action.

19. In a cylinder grinder of the character described, a mounting block adapted to rotate and reciprocate within a cylinder to be ground, a plurality of stones mounted axially 'on said block and adapted toexpand radially thereto, a spline shaft attached to said block and coaxial therewith, a gear splined on said spline shaft, means to rotate said block through said gear, reciproeating means mounted above said spline shaft and connected thereto, and a thrust bearing interposed between said spline shaft and said last named means permitting the rotation of the shaft independent of the means.

20. A cylinder grinding machine adapted to grind the cylinder of an engine having a crank shaft, a plurality of stones adapted to move axially in a cylinder and expand radially therein, a support above the stones adapted to permit rotation and reciprocation thereof, and a support below the stones including a member adapted to reciprocate with the stones, and a fixed member attached to the crank shaft at dead center and engaging said other member to form a guide for the lower end of the stones.

21. In a cylinder grinder of the character described comprising, a grinder mounting block adapted to rotate and reciprocate in the cylinder to be ground, a plurality of stones mounted axially on said block and adapted to expand radially thereto, a withdrawable support mounted beneath said block and comprising a guide cylinder fixed on the mounting block coaxially therewith, a guide rod mounted coax'ially with said guide cylinder and engaging the same to form a guide for the lower end of said block, and means to v withdraw the guide rod from said cylinder after a predetermined number of strokes of the grinder.

JOHN M. KROHN.

EUGENE .H. SIMPSON. 

